Apparatus for holding stacked workpieces and feeding the same

Abstract

An apparatus for holding a plurality of workpieces (W) in a stack on a pallet (22), supporting the workpieces (W) in place on the pallet (22) by a plurality of workpiece support rods (26), and transporting and transferring the uppermost workpiece by a workpiece gripping hand (50) provided with gripping fingers (54) to a desired position, is provided with elastic lifting springs (32) for continuously biasing the workpiece support rods (26) upward to support the workpieces (W) stably in place by the upright work support rods (26). The workpiece gripping hand (50) grips the uppermost workpiece (W) with the gripping fingers (54) without interference, after depressing the workpiece support rods (26) with a depressing plate (56) provided on the back side of the gripping fingers (54) so that the uppermost workpiece (W) is exposed above the upper ends of the workpiece support rods (26), and then transports the workpiece (W) to a desired position. When placing the workpiece (W) on the pallet (22) by the work gripping hand ( 50), the gripping fingers (54) release the workpiece (W) after the workpiece support rods (26) are depressed with the depressing plate (56).

We claim: 
     
       1. An apparatus for holding workpieces in a stack and feeding the same, including a workpiece feed means for holding a plurality of workpieces in a stack and sequentially feeding the same, and a workpiece transporting means having a workpiece gripping hand for gripping an uppermost workpiece among the workpieces held in a stack on the workpiece feed means, the workpiece transporting means removing a workpiece gripped by the workpiece gripping hand from said workpiece feed means and transferring said gripped workpiece to a desired position, characterized in that said workpiece feed means comprises a pallet, a plurality of upright workpiece support rods arranged at intervals in a circle on said pallet, to thereby stably support in place said plurality of workpieces stacked on a workpiece support surface of said pallet, means for depressing said plurality of workpiece support rods to a position below said workpiece support surface of said pallet, and a means for constantly and resiliently lifting said plurality of workpiece support rods upward to extended upward from said workpiece support surface of said pallet,   said workpiece gripping hand of said workpiece transporting means having a plurality of gripping fingers for releasably gripping a workpiece, and a depressing means disposed on a back side of said gripping fingers for simultaneously depressing said plurality of workpiece support rods of said workpiece feed means whereby said gripping fingers are brought to a position suitable for gripping said uppermost workpiece as said workpiece gripping hand is moved downward toward said uppermost workpiece.   
     
     
       2. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 1, wherein said workpieces have a cylindrical shape and the workpiece gripping hand is provided with at least three workpiece gripping fingers arranged at equal angular intervals in a circle. 
     
     
       3. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 2, wherein said depressing means of said workpiece gripping hand comprises a single annular plate having an outside diameter thereof greater than the diameter of said circle in which said workpiece support rods are arranged, and an inside diameter smaller than the diameter of said circle in which said workpiece support rods are arranged. 
     
     
       4. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 2, wherein said pallet is provided with a means for adjusting the diameter of said circle in which said workpiece support rods are arranged, depending on a diameter of each of said plurality of workpieces. 
     
     
       5. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 4, wherein said pallet comprises: a round and deep vessel-like-member having a bottom wall thereof provided with a plurality of circularly articulate slots for guiding said means for disposing said plurality of workpiece support rods for radial movement with respect to a given center; and   an adjusting plate rotatably held on an upper surface of said vessel-like-member and having a workpiece support surface thereof provided with a plurality of radial slots arranged at equal angular intervals for receiving said workpiece support rods therethrough.   
     
     
       6. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 1, wherein said disposing means of said plurality of workpiece support rods comprises a plurality of flanged, cylindrical bushings held on said pallet of said workpiece feed means each having a projecting portion projecting downward from the pallet, and wherein said resilient lifting means is a coil spring means provided between an outer surface of said cylindrical bushing and a lower end of each of said workpiece support rods. 
     
     
       7. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 6, wherein each of said workpiece support rods is guided by said cylindrical bushing for longitudinal movement between an uppermost position in which said workpiece support rod is lifted by a lifting force of said coil spring means and a lower position to which said workpiece support rod is moved against a resilience of said coil spring means to expose said uppermost workpiece of said plurality of stacked workpieces. 
     
     
       8. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 6, wherein each of said plurality of workpiece support rods is further provided with a support rod adjusting means for adjusting the uppermost position of the workpiece support rods above the upper surface of said pallet. 
     
     
       9. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 1, wherein said workpiece gripping hand comprises an end effector of an industrial robot. 
     
     
       10. An apparatus for holding a plurality of workpieces in a stack and feeding the same according to claim 9, wherein said workpiece transporting means comprises a robot arm of the industrial robot.